It's not that Trump is incapable of understanding how government works. He just doesn't care.
His whole life he's been the boss and people have done whatever he tells them to do. If they don't, he fires them and replaces them with someone who does. He was the one who claimed regarding his will vs what Governors can do with reopening that "The President has total authority."
This is the first time in his life where someone, ANYONE, has pushed back with trifling issues like "your office doesn't have that authority, Mr President", or "Mr President, it's completely illegal to do that", or "Mr President, that's unconstitutional", and they actually mean it and will not do what he wants.
I mean, Rudy and Barr are still all in on the Trump Train, but nearly everyone else is now in the wait and see mode.